What's the deal with pvc tank bottoms?

John08007 · Dec 26, 2020

I've seen many custom builds that mention pvc tank bottoms. What's the deal? First, silicone won't bond to pvc and pvc is not as strong as glass. Only positive i see is that it can be hit with a hammer without a panel blowout.

DaddyFish · Dec 26, 2020

I'm definitely watching this one!

HuduVudu · Dec 26, 2020

PVC will adhere to silicone. It isn't very strong bond but it is much stronger than acrylic. Also it being on the bottom it doesn't need to do much more than seal the seam. There isn't forces trying to pull the seam apart.

pcon · Dec 27, 2020

you can drop a rock on the bottom without worry. I would do a PVC bottom on a large build. just one less surface to worry about easily damaging.

don_chuwish · Dec 27, 2020

I’m curious what the full answer is as well.

John08007 · Dec 27, 2020

I was always worried about a point on a rock pushing against my glass bottom and breaking it so I put a piece of 3/8 or 1/2" clear acrylic on my bottom before I put rock and sand on. My opinion is that it will spread out the load making it safer.

count krunk · Dec 27, 2020

I believe it's still a glass bottom with a layer of pvc over it to provide protection against falling rocks

Joshcom · Dec 27, 2020

This is from reefsavy on their pvc bottom tank. The Phantom Bottom™ is a hybrid, multi-layered bottom designed for strength, durability, and aesthetics. Although, when finished its focus is on simplicity, producing it is anything but simple. The core layer and heart of the Phantom Bottom™ is glass, which is used for strength, rigidity and maximum adhesions, because nothing bonds better to glass than glass. The top and internal layer is a high impact ABS liner, which is designed to protect your glass from falling objects and is structurally bonded to the glass with a unique silicone sealant which helps absorb the impact, rather than transferring it to the glass . On bare bottom tanks, it’s particularly useful as it’s lightly textured surface creates a great foundation for corals to attach and grow, and prevents your aqua-scape from being directly on your glass. The bottom, external layer is closed cell PVC, which covers the bottom and prevents the glass from coming in contact with anything else. The PVC also protects the aquarium during transportation, and when placed on the stand it helps absorb pressure points. It also contributes to the structural integrity of the aquarium, as the sealant we use provides a structural bond. Unlike traditional custom aquariums, the glass core in the Phantom Bottom™ floats inside the aquarium, as oppose to under it. This eliminates the need for the 1″ white foam needed under the aquarium and allows the use of 1/4″ black neoprene which goes virtually undetected.

don_chuwish · Dec 27, 2020

And there you have it. Protects the glass both top and bottom - and requires special adhesives.

TerraFerma · Dec 27, 2020

Yup protection - I have a piece of Starboard (cutting board material) on the bottom of my glass tank just for that purpose.

vetteguy53081 · Dec 27, 2020

It is associated with both cost and a good point of whats the use iof using glass when its going to be covered with rock and sand. Also reduces dry weight.

Spieg · Dec 27, 2020

I'd probably use a PVC or ABS sheet to protect the glass bottom if I was doing a bare bottom tank. Also if you have an open top stand it prevents being able to see your sump through the bottom of the tank. Don't really see it as necessary in a sand substrate tank.